The present invention is an apparatus for fitting retaining or locking pins on a support mandrel made from a material able to receive such pins by direct pressure fitting.
For the production of hollow members of revolution formed from wires extending in at least three different directions not in the same plane, French Pat. No. 2,408,676 already proposes fitting retaining pins radially on a support mandrel and then arranging superimposed wire layers in the longitudinal and circumferential passages formed between the retaining pins by using winding and weaving. The thus obtained member is impregnated with a thermosetting resin, whereof the polymerization makes it possible to harden the entity.
In practice, at least the peripheral part of the mandrel is made from a rigid foam, such as a phenolic or polyurethane foam. The retaining pins are generally made from prepolymerized fibrous elements.
In view of the homogeneity defects of the foam of the mandrel and the straightness defects of the retaining pins, the production of thick members with the apparatus described in French Pat. No. 2,408,676 is subject to numerous difficulties. To solve these difficulties, French Pat. No. 2,509,706 proposes making holes beforehand in the mandrel before fitting the pins.
Despite the good results obtained with the apparatus described in the latter patent, both it and the apparatus according to French Pat. No. 2,408,676 have certain limitations, mainly due to the need of supplying them with previously cut retaining pins.
In both cases the retaining pins are supplied to the fitting apparatus by gravity. Thus, the apparatuses can only be positioned vertically above the mandrel, which suffers from obvious disadvantages, particularly during the production of large members, because the supply apparatus is then difficult to access and prevents any removal of the member from the top using lifting gear.
Moreover, the supply of cut retaining pins to existing fitting apparatuses generally takes place with the aid of vibrating bowls, whose structure makes it impossible to fit very long retaining pins.
Finally, in the apparatus described in French Pat. No. 2,509,706, a drum system is used for intermediate storage and alignment of retaining pins prior to their fitting. This complicates the structure of the machine and consequently increases its cost and the breakdown risks.